What did the early Greek philosophers think about animals and their lives? How did they view plants? And, ultimately, what type of relationship did they envisage between all sorts of living beings? On these topics there is evidence of a prolonged investigation by several Presocratics. However, scholarship has paid little attention to these issues and to the surprisingly modern development they received in Presocratics’ doctrines. This book fills this lacuna through a detailed (and largely unprecedented) analysis of the extant evidence. The volume includes also the first extensive collection of the ancient sources pertaining to living beings and life in early Greek philosophy, organized chronologically and thematically.